CN117393860B

CN117393860B - Quick-charging electrolyte, battery filling method and battery

Info

Publication number: CN117393860B
Application number: CN202311699900.5A
Authority: CN
Inventors: 王姣姣; 赵彬涛; 张悦; 曾涛
Original assignee: Tianjin Lishen Battery JSCL; Lishen Qingdao New Energy Co Ltd
Current assignee: Tianjin Lishen Battery JSCL; Lishen Qingdao New Energy Co Ltd
Priority date: 2023-12-12
Filing date: 2023-12-12
Publication date: 2024-02-27
Anticipated expiration: 2043-12-12
Also published as: CN117393860A

Abstract

The application provides a fast-charging electrolyte, a battery liquid injection method and a battery, wherein the fast-charging electrolyte comprises lithium salt, a carbonate solvent, a carboxylate solvent, vinylene carbonate, a fluorocarbonate additive, a phosphite additive, a sulfur-containing additive and a fluorophenylcarboxylate additive. The quick-charging electrolyte, the battery liquid injection method and the battery are simple in formula, convenient to manufacture, capable of effectively improving the quick-charging performance of the battery, high-temperature and low-temperature performance of the battery, good in circulating effect and long in service life.

Description

Quick-charging electrolyte, battery filling method and battery

Technical Field

The application relates to the technical field of batteries, in particular to a quick-charge electrolyte solution method, a battery electrolyte injection method and a battery.

Background

In the field of new energy, the fast charge capability and the low-temperature operation capability of the battery are always key factors for determining the competitiveness of the battery, and in order to further improve the competitiveness, both the high-temperature performance and the cycle performance are required to be considered. At present, means for improving the quick charge performance and the high and low temperature performance of the battery mainly comprises the step of introducing a specific functional additive into an electrolyte formula.

Some techniques disclose a fast-charging electrolyte, the additive being Allyloxy trimethyl silicon (AMSL) utilizes the synergistic effect between the AMSL and the solvent to improve the quick charge, but the chain siloxane is not easy to be adsorbed on the graphite surface, and does not contain strong electronegative atoms or groups in the structure, so Li cannot be well weakened ⁺ Bonding strength with strongly coordinating solvents. Some techniques disclose a fast-charging electrolyte, wherein the additive is lithium nitrate, which is favorable for forming Li-containing electrolyte on the surface of the anode ₃ The interfacial film of N improves the quick charge and cycle performance, but lithium nitrate is an inorganic additive, has poor compatibility with organic electrolyte and has higher preparation cost. Some technologies disclose a nonaqueous electrolyte, wherein the selected additives are fluorobenzene sulfonate and nitrogen-containing heterocyclic dinitrile compound, and the fluorobenzene sulfonate and the nitrogen-containing heterocyclic dinitrile compound are cooperated to generate an antioxidation protection layer at the positive electrode, but only the stability of the battery under high voltage is focused, the improvement of electrode interface dynamics is not focused, and the improvement of quick charge and low temperature performance is not involved. In other technologies, a low-temperature electrolyte is disclosed, the solvent is acetonitrile and 1, 1, 2, 2-tetrafluoro-1- (trifluoromethoxy) ethane, the additive is sulfones and boroxine substances, and the low-temperature electrolyte has a better low-temperature improving effect, but the electrolyte system has a single function and cannot achieve both quick charging and high-temperature performance.

Therefore, an electrolyte solution that can achieve both the fast charge and high and low temperature performance of the battery is needed.

Disclosure of Invention

Accordingly, the present application is directed to a fast-charging electrolyte, a method for charging a battery, and a battery for solving the above-mentioned problems.

In a first aspect of the present application, a fast-charging electrolyte is provided that includes a lithium salt, a carbonate solvent, a carboxylate solvent, a vinylene carbonate, a fluorocarbonate additive, a phosphite additive, a sulfur-containing additive, and a fluorophenylcarboxylate additive.

Further, the chemical formula of the fluorinated phenyl carboxylate additive is:wherein R is a perhalogenated aryl group or a perhalogenated alkyl group having 1 to 6 carbon atoms, R1, R2, R3, R4 and R5 are each halogen, whereinAt least one of R1, R2, R3, R4 and R5 is fluorine.

Further, the lithium salt is one or more of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide or lithium bis (trifluoromethylsulfonyl) imide; the carbonic ester solvent is one or more of ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate or propylene carbonate; the carboxylic ester solvent is one or more of methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl formate or ethyl formate; the fluorocarbonate additive is one or more of fluoroethylene carbonate, monofluoromethylethylene carbonate, difluoromethyl ethylene carbonate or trifluoromethyl ethylene carbonate; the phosphite additive is one or more of tris (trimethylsilane) phosphite, triphenyl phosphite, trimethyl phosphite or tris (2, 2-trifluoroethyl) phosphite; the sulfur-containing additive is one or more of vinyl sulfate, methylene methane disulfonate, 1, 3-propane sultone or propenyl-1, 3-sultone; the fluoro phenyl carboxylate additive is pentafluorophenyl trifluoroacetate or 2,3,4,5, 6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl formate.

Further, the fast-charging electrolyte comprises a first electrolyte for first filling of the battery and a second electrolyte for second filling of the battery; the first electrolyte includes a first lithium salt, a first carbonate solvent, a first carboxylate solvent, vinylene carbonate, a fluorocarbonate additive, and a phosphite additive; the second electrolyte includes a second lithium salt, a second carbonate solvent, a second carboxylate solvent, vinylene carbonate, a sulfur-containing additive, and a fluorophenylcarboxylate additive.

Further, the first electrolyte includes 11 to 15 parts by weight of the first lithium salt, 45 to 60 parts by weight of the first carbonate solvent, 25 to 35 parts by weight of the first carboxylate solvent, 1.5 to 2.5 parts by weight of vinylene carbonate, 0.2 to 1.5 parts by weight of the fluorocarbonate additive, and 0.1 to 1 part by weight of the phosphite additive; the second electrolyte comprises 11-15 parts by weight of the second lithium salt, 40-50 parts by weight of the second carbonate solvent, 20-25 parts by weight of the second carboxylate solvent, 3.5-9.5 parts by weight of vinylene carbonate, 2.5-10 parts by weight of the sulfur-containing additive and 1-5 parts by weight of the fluorophenylcarboxylate additive.

Further, the second electrolyte includes 2.5 parts by weight of the fluorophenylcarboxylate additive.

Further, the first lithium salt is lithium hexafluorophosphate, the first carbonate solvent is ethylene carbonate and dimethyl carbonate, the first carboxylate solvent is ethyl acetate, the fluorocarbonate additive is fluoroethylene carbonate, and the phosphite additive is tris (trimethylsilane) phosphite; the second lithium salt is lithium hexafluorophosphate, the second carbonate solvent is ethylene carbonate and dimethyl carbonate, the second carboxylate solvent is ethyl acetate, the sulfur-containing additive is ethylene sulfate, methylene methane disulfonate and 1, 3-propane sultone, and the fluorophenyl carboxylate additive is pentafluorophenyl trifluoroacetate.

Further, the first electrolyte accounts for 70-90% of the fast-charging electrolyte by mass.

In a second aspect of the present application, there is provided a battery filling method using the fast-charging electrolyte according to the first aspect, the battery filling method comprising: performing first liquid injection on the battery by using the first electrolyte; pre-forming the battery after the first liquid injection; performing secondary injection on the battery by using the second electrolyte; and carrying out primary formation on the battery after the secondary liquid injection.

In a third aspect of the present application, there is provided a battery comprising a positive electrode, a negative electrode, a separator and a fast-charging electrolyte as described in the first aspect above.

As can be seen from the foregoing, the present application provides a fast-charge electrolyte, battery pack method and battery, the fast-charge electrolyte comprising a lithium salt, a carbonate solvent, a carboxylate solvent, a vinylene carbonate, a fluorocarbonate additive, a phosphite additive, a sulfur-containing additive and a fluorophenylcarboxylate additive; introducing a combination of carbonate and carboxylate solvents to reduce the overall solvent setThe freezing point is used for improving the fluidity at low temperature and improving the low-temperature performance of the battery; the fluorocarbonate additive and the phosphite additive are introduced, and in-situ Lewis acid-base reaction of the fluorocarbonate additive and the phosphite additive is carried out to generate a complex with high HOMO (Highest Occupied Molecular Orbital ) and low LUMO (Lowest Unoccupied Molecular Orbital, lowest unoccupied molecular orbital), so that positive and negative effects are well protected, and the high-temperature stability of the battery is improved; introducing sulfur-containing additive to form interface film with low impedance and high conductivity to raise Li ⁺ Mobility; the introduction of the fluorinated phenyl carboxylate additive can greatly promote the desolvation process, realize the rapid and stable charging, and compared with the electrolyte without the fluorinated phenyl carboxylate additive, the battery manufactured by the rapid charging electrolyte can improve the constant current charging ratio and the 60 ℃ storage performance, and remarkably improve the 45 ℃ cycle performance, -10 ℃ cycle performance and the low-temperature charging performance through experimental tests; the quick-charging electrolyte, the battery liquid injection method and the battery are simple in formula and convenient to manufacture, can effectively improve the quick-charging performance of the battery, and meanwhile improve the high-temperature and low-temperature performance of the battery, and are good in circulating effect and long in service life.

Drawings

In order to more clearly illustrate the technical solutions of the present application or related art, the drawings that are required to be used in the description of the embodiments or related art will be briefly described below, and it is apparent that the drawings in the following description are only embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort to those of ordinary skill in the art.

Fig. 1 is a schematic diagram of a 45 ℃ cycle performance test of a battery after injection of the examples and comparative examples of the present application.

Fig. 2 is a schematic diagram of a-10 ℃ cycle performance test of the battery after the injection of the examples and the comparative examples of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below with reference to the accompanying drawings.

It should be noted that unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present application belongs. The terms "first," "second," and the like, as used in embodiments of the present application, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

In the field of new energy, the fast charge capability and the low-temperature operation capability of the battery are always key factors for determining the competitiveness of the battery, and in order to further improve the competitiveness, both the high-temperature performance and the cycle performance are required to be considered. At present, means for improving the quick charge performance and the high and low temperature performance of the battery mainly comprises the step of introducing a specific functional additive into an electrolyte formula. In some techniques, a fast charge electrolyte is disclosed, the additive is allyloxy trimethyl silicon (AMSL), the AMSL can be reduced in the anode to form a stable SEI (solid electrolyte interface ) film, the synergistic effect between the AMSL and the solvent is utilized to improve the fast charge, but the chain siloxane is not easy to adsorb on the graphite surface, the structure does not contain strong electronegative atoms or groups, thus the Li cannot be weakened well ⁺ Bonding strength with strongly coordinating solvents. Some techniques disclose a fast-charging electrolyte, wherein the additive is lithium nitrate, which is favorable for forming Li-containing electrolyte on the surface of the anode ₃ The interfacial film of N improves the quick charge and cycle performance, but lithium nitrate is an inorganic additive, has poor compatibility with organic electrolyte and has higher preparation cost. Some techniques disclose a nonaqueous electrolyte, the additives selected are The fluorobenzene sulfonate and the nitrogen-containing heterocyclic dinitrile compound are cooperated to generate an anti-oxidation protective layer at the positive electrode, but only the stability of the battery under high voltage is improved, the improvement of electrode interface dynamics is not focused, and the quick charge and low temperature performance are not improved. In other technologies, a low-temperature electrolyte is disclosed, the solvent is acetonitrile and 1, 1, 2, 2-tetrafluoro-1- (trifluoromethoxy) ethane, the additive is sulfones and boroxine substances, and the low-temperature electrolyte has a better low-temperature improving effect, but the electrolyte system has a single function and cannot achieve both quick charging and high-temperature performance. Therefore, an electrolyte solution that can achieve both the fast charge and high and low temperature performance of the battery is needed.

In the process of realizing the application, the lithium ion battery is mainly subjected to double restriction of positive electrode lithium removal dynamics and negative electrode lithium intercalation dynamics during quick charge, and particularly, polarization and lithium precipitation are easily caused by slow negative electrode lithium intercalation process, so that the battery capacity is attenuated. Therefore, charge transfer at the electrode interface becomes a fast charge-determining step due to desolvation compared to Li ⁺ Diffusion inside the electrolyte and the electrode has a higher energy barrier, and therefore, the key to improving the fast charge capacity is to promote the desolvation process at the interface. The carboxylate solvent has a lower freezing point than the carbonate solvent, and is expected to improve the current situation of difficult low-temperature operation. Fluorocarbonate is a preferred film forming additive of a fast-charging system because of being capable of generating a high-conductivity SEI film rich in LiF, however, the HOMO energy level of the materials is low, protective CEI (Chemical-Electrochemical Interface, electrochemical interface) cannot be formed at the positive electrode, and transition metal ions are easy to promote the decomposition of the materials at high temperature, so that the battery performance is degraded, and therefore, the control of the film forming sequence of the additive and the improvement of the HOMO energy level of the fluorocarbonate materials are helpful for improving the high-temperature performance. In addition, sultone or sulfate additives are advantageous in forming a low-impedance interfacial film, promoting Li ⁺ And the circulation performance is improved.

The technical scheme of the present application will be described in detail by specific examples.

In some embodiments of the present application, a fast-charging electrolyte is provided that includes a lithium salt, a carbonate solvent, a carboxylate solvent, a vinylene carbonate, a fluorocarbonate additive, a phosphite additive, a sulfur-containing additive, and a fluorophenylcarboxylate additive.

Lithium salts are used to participate in electrochemical reactions.

Vinylene carbonate can be used as an organic film-forming additive and an overcharge protection agent.

The carbonic ester solvent and the carboxylic ester solvent are combined, so that the solidifying point of the whole solvent is reduced, the fluidity and the conductivity at low temperature are improved, and the low-temperature performance of the battery is improved.

The fluoro carbonate additive and the phosphite additive react with each other through in-situ Lewis acid and alkali to generate a complex with high HOMO (Highest Occupied Molecular Orbital ) and low LUMO (Lowest Unoccupied Molecular Orbital, lowest unoccupied molecular orbital), the complex can be respectively oxidized and reduced preferentially at the positive electrode and the negative electrode to generate high-stability CEI and SEI inorganic interface layers containing F/P/Si, the positive electrode and the negative electrode can be well protected, and meanwhile, the fluoro carbonate substance is easy to decompose at high temperature to cause the capacity attenuation of the battery, and the generated complex can be decomposed into a stable interface film as much as possible during the pre-formation, so that the high-temperature stability of the battery is improved.

The sulfur-containing additive forms an interfacial film with low impedance and high conductivity, thereby improving Li ⁺ Mobility.

The fluoro phenyl carboxylate additive is used for regulating and controlling an interface solvation structure, a strong electronegative group and a benzene ring plane generate p-pi conjugation, so that the benzene ring is in an electron-deficient state, and is adsorbed on the surface of a negative electrode rich in a large number of delocalized electrons in a pi-pi stacking way, and meanwhile, the strong electronegative group, especially fluorine, can generate strong hydrogen bond interaction with alkyl hydrogen of an ester solvent, so that Li is weakened ⁺ The coordination strength between the electrolyte and the solvent can greatly promote the desolvation process, realize the rapid and stable charge, and compared with the electrolyte without the fluorinated phenyl carboxylate additive, the battery manufactured by the rapid charge electrolyte can improve the constant current charge ratio and the 60 ℃ storage performance, and remarkably improve the 45 ℃ cycle performance, -10 ℃ cycle performance and the low-temperature charge performance through experimental tests.

The fast-charging electrolyte has the advantages of simple formula, convenient manufacture, capability of effectively improving the fast-charging performance of the battery, high and low temperature performance of the battery, good circulating effect and long service life.

In some embodiments, the fluorophenylcarboxylate additive has the formula: Wherein R is a perhalogenated aromatic group or a perhalogenated alkyl group having 1 to 6 carbon atoms, at least one of R1, R2, R3, R4 and R5 is fluorine, and the balance is halogen.

R is perhalogenated aryl or perhalogenated alkyl containing 1-6 carbon atoms, such as trifluoromethyl, pentachloroethyl or pentafluorophenyl, etc., and the use of the perhalogenated groups avoids the creation of intramolecular hydrogen bonds, which facilitates desolvation.

R1, R2, R3, R4 and R5 are halogen, halogen such as fluorine, chlorine, bromine or iodine, and the like, and for example, 1, 2, 3, 4 or 5 of R1, R2, R3, R4 and R5 are fluorine, so that at least one fluorine is ensured to be contained, the electronegativity of fluorine atoms is strongest, the electron withdrawing capability is strongest, fluorine, carbon of benzene ring, oxygen of carboxyl and the like are of a two-electron layer structure, the overall conjugation effect is strongest, a better conjugation system of the structure is ensured, and the low-temperature quick charge effect is improved.

The phenyl ring adopted in the fluorinated phenyl carboxylate additive has stronger conjugation effect compared with chain alkane, more tends to positive charge, is favorable for desolvation, and can obviously improve constant-current charge ratio and 60 ℃ storage performance compared with the fluorinated alkyl carboxylate additive, and obviously improve 45 ℃ cycle performance, -10 ℃ cycle performance and low-temperature charge performance through experimental tests.

In some embodiments, the lithium salt is one or more of lithium hexafluorophosphate, lithium bis-fluorosulfonyl imide, or lithium bis-trifluoromethylsulfonyl imide; the carbonic ester solvent is one or more of ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate or propylene carbonate; the carboxylic ester solvent is one or more of methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl formate or ethyl formate; the fluorocarbonate additive is one or more of fluoroethylene carbonate, monofluoromethylethylene carbonate, difluoromethyl ethylene carbonate or trifluoromethyl ethylene carbonate; the phosphite additive is one or more of tris (trimethylsilane) phosphite, triphenyl phosphite, trimethyl phosphite or tris (2, 2-trifluoroethyl) phosphite; the sulfur-containing additive is one or more of vinyl sulfate, methylene methane disulfonate, 1, 3-propane sultone or propenyl-1, 3-sultone; the fluoro phenyl carboxylate additive is pentafluorophenyl trifluoroacetate or 2,3,4,5, 6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl benzoate.

Lithium salts such as lithium hexafluorophosphate and lithium difluorosulfonimide; carbonate solvents are, for example, ethylene carbonate and ethylmethyl carbonate; carboxylic ester solvents such as methyl acetate and ethyl acetate; fluorocarbonate additives such as fluoroethylene carbonate and monofluoromethylethylene carbonate; phosphite additives are, for example, tris (trimethylsilane) phosphite and triphenyl phosphite; sulfur-containing additives such as vinyl sulfate and methylene methane disulfonate; the fluoro phenyl carboxylate additive is pentafluorophenyl trifluoroacetate or 2,3,4,5, 6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl benzoate, wherein the CAS number of the pentafluorophenyl trifluoroacetate is 14533-84-7,2,3,4,5,6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl benzoate and the CAS number of the pentafluorophenyl trifluoroacetate is 14533-82-5, which can be directly obtained.

In some embodiments, the fast-charge electrolyte comprises a first electrolyte for a first fill of the battery and a second electrolyte for a second fill of the battery; the first electrolyte includes the lithium salt, the carbonate solvent, the carboxylate solvent, the vinylene carbonate, the fluorocarbonate additive, and the phosphite additive; the second electrolyte includes the lithium salt, the carbonate solvent, the carboxylate solvent, the vinylene carbonate, the sulfur-containing additive, and the fluorophenylcarboxylate additive.

The quick-charging electrolyte can be used for secondary electrolyte injection of the battery, and comprises a first electrolyte for primary electrolyte injection of the battery and a second electrolyte for secondary electrolyte injection of the battery, and the electrical property of the battery can be effectively improved compared with that of primary electrolyte injection through secondary electrolyte injection.

The first electrolyte is introduced with the fluoro-carbonate additive and the phosphite additive, plays a role in protecting the positive electrode and the negative electrode well, and is beneficial to improving the high-temperature stability of the battery. And the second electrolyte is introduced with the fluorinated phenyl carboxylate additive to promote the desolvation process, so that the rapid, stable and quick filling is realized. And a sulfur-containing additive is introduced into the second electrolyte, so that an interfacial film with low impedance and high conductivity is formed, the kinetics of interfacial lithium intercalation is improved, and the cycle performance under rapid charging is improved.

The first electrolyte contains a fluorocarbonate additive and a phosphite additive, and does not contain a sulfur-containing additive and a fluorophenylcarboxylate additive; the second electrolyte contains sulfur-containing additives and fluorophenylcarboxylate additives, does not contain fluorocarbonate additives and phosphite additives, can form stable CEI and SEI inorganic interface films, and simultaneously promotes the desolvation process; experiments prove that compared with the electrolyte combination of one-time injection electrolyte containing all components or electrolyte combination reversely arranged relative to the first electrolyte and the second electrolyte, the quick-charging electrolyte prepared in sequence according to the embodiment has better quick-charging performance, high-temperature performance and low-temperature performance and good cycle performance.

In some embodiments, the first electrolyte comprises 11-15 parts by weight of the lithium salt, 45-60 parts by weight of the carbonate solvent, 25-35 parts by weight of the carboxylate solvent, 1.5-2.5 parts by weight of the vinylene carbonate, 0.2-1.5 parts by weight of the fluorocarbonate additive, and 0.1-1 parts by weight of the phosphite additive; the second electrolyte comprises 11-15 parts by weight of the lithium salt, 40-50 parts by weight of the carbonate solvent, 20-25 parts by weight of the carboxylate solvent, 3.5-9.5 parts by weight of the vinylene carbonate, 2.5-10 parts by weight of the sulfur-containing additive, and 1-5 parts by weight of the fluorophenylcarboxylate additive.

In the first electrolyte, the parts by weight of the lithium salt is, for example, 11, 12, 13, 14, or 15, the parts by weight of the carbonate solvent is, for example, 45, 50, 55, or 60, the parts by weight of the carboxylate solvent is, for example, 25, 30, or 35, the parts by weight of the vinylene carbonate is, for example, 1.5, 2, or 2.5, the parts by weight of the fluorocarbonate additive is, for example, 0.2, 0.5, 1, or 1.5, and the parts by weight of the phosphite additive is, for example, 0.1, 0.5, or 1.

In the second electrolyte, the parts by weight of the lithium salt is, for example, 11, 12, 13, 14, 15, or the like, the parts by weight of the carbonate solvent is, for example, 40, 45, or 50, or the like, the parts by weight of the carboxylate solvent is, for example, 20, 21, 22, 23, 24, or 25, or the like, the parts by weight of the vinylene carbonate is, for example, 3.5, 5, or 9.5, or the like, the parts by weight of the sulfur-containing additive is, for example, 2.5, 5, or 10, or the like, and the parts by weight of the fluorophenylcarboxylate additive is, for example, 1, 2, 3, 4, or 5, or the like.

The low-content vinylene carbonate is arranged in the first electrolyte, and the relatively high-content vinylene carbonate is arranged in the second electrolyte, so that the membrane repair in the later period of circulation can be ensured.

In some embodiments, the second electrolyte includes 2.5 parts by weight of the fluorophenylcarboxylate additive.

Experiments prove that when the second electrolyte comprises 2.5% of fluorinated phenyl carboxylate additive by mass percent, the battery has optimal electrical property, the constant current charge ratio at 1C multiplying power is 0.991,5C, the constant current charge ratio at 45 ℃ is 0.888, the battery capacity retention rate after 800 times of 45 ℃ circulation is 90.51%, the battery capacity retention rate after 100 times of-10 ℃ circulation is 98.55%, the battery capacity retention rate at-30 ℃ is 21.99% based on 25 ℃ discharge capacity, the battery residual capacity after 2 months of storage at 60 ℃ is 97.05%, and the recovery capacity is 97.44%.

In some embodiments, the lithium salt is lithium hexafluorophosphate, the carbonate solvent is ethylene carbonate and dimethyl carbonate, the carboxylate solvent is ethyl acetate, the fluorocarbonate additive is fluoroethylene carbonate, the phosphite additive is tris (trimethylsilane) phosphite, the sulfur-containing additive is ethylene sulfate, methylene methane disulfonate, and 1, 3-propane sultone, and the fluorophenylcarboxylate additive is pentafluorophenyl trifluoroacetate.

In some embodiments, the first electrolyte accounts for 70% -90% of the mass of the fast-charging electrolyte, that is, the liquid injection amount of the first electrolyte accounts for 70% -90%, for example, 70%, 80% or 90% of the total liquid injection amount of the fast-charging electrolyte, so that the pre-formation can be fully formed into a film, and the battery performance is ensured.

In some embodiments of the present application, a method for filling a battery is provided, using the fast-charging electrolyte as described in any one of the embodiments above, the method for filling a battery includes:

s1, performing first injection on the battery by using the first electrolyte.

Preparing a first electrolyte according to a preset proportion, and injecting the first electrolyte into the battery.

S2, preforming the battery after the first liquid injection.

The pre-formed product mainly consumes the fluorocarbonate additive and the phosphite additive in the first electrolyte, the fluorocarbonate additive and the phosphite additive are charged step by small current, the SOC of the battery is charged to about 40%, and then the gas generated by the pre-formed product is discharged for the second injection, so that the film forming stability is better.

And S3, performing secondary liquid injection on the battery by using the second electrolyte.

And preparing a second electrolyte according to a preset proportion, and injecting the second electrolyte into the battery.

And S4, carrying out primary formation on the battery after the secondary liquid injection.

The main formation mainly consumes the sulfur-containing additive with low impedance in the second electrolyte to form an interfacial film with low impedance, and the battery is fully charged with constant current and constant voltage.

In some embodiments, the first electrolyte has a fill level of 70% -90%, such as 70%, 80%, 90% or the like, by mass of the total fill level of the fast-fill electrolyte.

The battery prepared by the battery liquid injection method has good quick charge performance, high and low temperature performance and stable circulation.

In some embodiments of the present application, a battery is provided that includes a positive electrode, a negative electrode, a separator, and a fast-charging electrolyte as described in any of the embodiments above.

The stacking type of the battery is, for example, a winding type battery or a lamination type battery, the structure type is, for example, a square shell battery, a soft package battery or a cylindrical battery, etc., the battery is not particularly limited, and the battery has strong stability, good circulation effect and long service life.

Example 1

The quick-charge electrolyte comprises 13.5 parts by weight of lithium hexafluorophosphate, 24.91 parts by weight of ethylene carbonate, 28.39 parts by weight of dimethyl carbonate, 27.4 parts by weight of ethyl acetate, 3.0 parts by weight of vinylene carbonate, 0.5 part by weight of fluoroethylene carbonate, 0.5 part by weight of methylene methane disulfonate, 0.6 part by weight of vinyl sulfate, 0.2 part by weight of tris (trimethylsilane) phosphite, 0.5 part by weight of 1, 3-propane sultone and 0.5 part by weight of pentafluorophenyl trifluoroacetate.

The quick-charging electrolyte is used for filling the battery by adopting a one-time filling method.

Example 2

The fast-charging electrolyte comprises a first electrolyte and a second electrolyte, wherein the first electrolyte accounts for 80% of the fast-charging electrolyte in percentage by mass.

The first electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 25.81 parts by weight of ethylene carbonate, 29.42 parts by weight of dimethyl carbonate, 28.39 parts by weight of ethyl acetate, 2.0 parts by weight of vinylene carbonate, 0.63 parts by weight of fluoroethylene carbonate, and 0.25 parts by weight of tris (trimethylsilane) phosphite.

The second electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 21.76 parts by weight of ethylene carbonate, 24.81 parts by weight of dimethyl carbonate, 23.94 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, 2.5 parts by weight of 1, 3-propane sultone, and 1.0 part by weight of pentafluorophenyl trifluoroacetate.

The battery is injected by the quick-filling electrolyte by adopting a secondary injection method, and the injection amount of the first electrolyte accounts for 80% of the total injection amount of the quick-filling electrolyte by mass percent.

Example 3

The second electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 21.3 parts by weight of ethylene carbonate, 24.28 parts by weight of dimethyl carbonate, 23.43 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, 2.5 parts by weight of 1, 3-propane sultone, and 2.5 parts by weight of pentafluorophenyl trifluoroacetate.

Example 4

The second electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 20.83 parts by weight of ethylene carbonate, 23.75 parts by weight of dimethyl carbonate, 22.92 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, 2.5 parts by weight of 1, 3-propane sultone, and 4.0 parts by weight of pentafluorophenyl trifluoroacetate.

Example 5

The second electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 20.52 parts by weight of ethylene carbonate, 23.4 parts by weight of dimethyl carbonate, 22.58 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, 2.5 parts by weight of 1, 3-propane sultone, and 5.0 parts by weight of pentafluorophenyl trifluoroacetate.

Example 6

The fast-charging electrolyte comprises a first electrolyte and a second electrolyte, wherein the first electrolyte accounts for 70% of the fast-charging electrolyte in percentage by mass.

The first electrolyte included 15 parts by weight of lithium hexafluorophosphate, 30 parts by weight of ethylene carbonate, 30 parts by weight of dimethyl carbonate, 35 parts by weight of ethyl acetate, 2.5 parts by weight of vinylene carbonate, 1.5 parts by weight of fluoroethylene carbonate, and 1 part by weight of tris (trimethylsilane) phosphite.

The second electrolyte comprises 15 parts by weight of lithium hexafluorophosphate, 25 parts by weight of ethylene carbonate, 25 parts by weight of dimethyl carbonate, 25 parts by weight of ethyl acetate, 9.5 parts by weight of vinylene carbonate, 3 parts by weight of methylene methane disulfonate, 4 parts by weight of vinyl sulfate, 3 parts by weight of 1, 3-propane sultone, and 5 parts by weight of 2,3,4,5, 6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl benzoate.

The battery is injected by the quick-filling electrolyte by adopting a secondary injection method, and the injection amount of the first electrolyte accounts for 70% of the total injection amount of the quick-filling electrolyte by mass.

Example 7

The fast-charging electrolyte comprises a first electrolyte and a second electrolyte, wherein the first electrolyte accounts for 90% of the fast-charging electrolyte in percentage by mass.

The first electrolyte comprises 11 parts by weight of lithium difluorosulfimide, 20 parts by weight of ethylene carbonate, 25 parts by weight of dimethyl carbonate, 25 parts by weight of ethyl acetate, 1.5 parts by weight of vinylene carbonate, 0.2 part by weight of trifluoromethyl ethylene carbonate and 0.1 part by weight of tris (2, 2-trifluoroethyl) phosphite.

The second electrolyte comprises 11 parts by weight of lithium difluorosulfimide, 20 parts by weight of ethylene carbonate, 20 parts by weight of dimethyl carbonate, 20 parts by weight of ethyl acetate, 3.5 parts by weight of vinylene carbonate, 0.5 part by weight of methylene methane disulfonate, 1.5 parts by weight of vinyl sulfate, 0.5 part by weight of propenyl-1, 3-sultone and 1 part by weight of pentafluorophenyl trifluoroacetate.

The battery is injected by the quick-filling electrolyte by adopting a secondary injection method, and the injection amount of the first electrolyte accounts for 90% of the total injection amount of the quick-filling electrolyte by mass.

Comparative example 1

The electrolyte comprises 13.5 parts by weight of lithium hexafluorophosphate, 25.06 parts by weight of ethylene carbonate, 28.57 parts by weight of dimethyl carbonate, 27.57 parts by weight of ethyl acetate, 3.0 parts by weight of vinylene carbonate, 0.5 part by weight of fluoroethylene carbonate, 0.5 part by weight of methylene methane disulfonate, 0.6 part by weight of vinyl sulfate, 0.2 part by weight of tris (trimethylsilane) phosphite and 0.5 part by weight of 1, 3-propane sultone.

The electrolyte is used for injecting the battery by adopting a one-time injection method.

Comparative example 2

The electrolyte comprises 13.5 parts by weight of lithium hexafluorophosphate, 24.91 parts by weight of ethylene carbonate, 28.39 parts by weight of dimethyl carbonate, 27.4 parts by weight of ethyl acetate, 3.0 parts by weight of vinylene carbonate, 0.5 part by weight of fluoroethylene carbonate, 0.5 part by weight of methylene methane disulfonate, 0.6 part by weight of vinyl sulfate, 0.2 part by weight of tris (trimethylsilane) phosphite, 0.5 part by weight of 1, 3-propane sultone and 0.5 part by weight of undecyl trifluoroacetate; wherein, the CAS number of the trifluoroacetate undecanovalerate is 42133-36-8.

Comparative example 3

The electrolyte combination comprises a first electrolyte and a second electrolyte, wherein the first electrolyte accounts for 80% of the electrolyte combination in percentage by mass.

The second electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 22.07 parts by weight of ethylene carbonate, 25.16 parts by weight of dimethyl carbonate, 24.27 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, and 2.5 parts by weight of 1, 3-propane sultone.

The electrolyte combination is used for injecting the battery by adopting a secondary injection method, and the injection amount of the first electrolyte accounts for 80% of the total injection amount of the electrolyte combination in percentage by mass.

Comparative example 4

The first electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 25.62 parts by weight of ethylene carbonate, 29.20 parts by weight of dimethyl carbonate, 28.18 parts by weight of ethyl acetate, 2.0 parts by weight of vinylene carbonate, 0.63 parts by weight of fluoroethylene carbonate, 0.25 parts by weight of tris (trimethylsilane) phosphite, and 0.625 parts by weight of pentafluorophenyl trifluoroacetate.

Comparative example 5

The first electrolyte included 13.5 parts by weight of lithium hexafluorophosphate, 26.08 parts by weight of ethylene carbonate, 29.73 parts by weight of dimethyl carbonate, 28.69 parts by weight of ethyl acetate, and 2.0 parts by weight of vinylene carbonate.

The second electrolyte includes 13.5 parts by weight of lithium hexafluorophosphate, 20.22 parts by weight of ethylene carbonate, 23.05 parts by weight of dimethyl carbonate, 22.24 parts by weight of ethyl acetate, 7.0 parts by weight of vinylene carbonate, 2.5 parts by weight of fluoroethylene carbonate, 2.5 parts by weight of methylene methane disulfonate, 3.0 parts by weight of vinyl sulfate, 1.0 part by weight of tris (trimethylsilane) phosphite, 2.5 parts by weight of 1, 3-propane sultone, and 2.5 parts by weight of pentafluorophenyl trifluoroacetate.

The preparation methods of the batteries according to the foregoing examples and comparative examples include: lithium iron phosphate, a conductive agent CNT (conductive carbon nano tube), a conductive agent SP (conductive carbon black) and a binder PVDF (polyvinylidene fluoride) according to a mass ratio of 96:0.5:1.0:2.5 dispersing in NMP (N-methyl pyrrolidone) solvent uniformly, stirring under vacuum for a period of time to obtain positive electrode slurry with solid content of 60%, uniformly coating the positive electrode slurry on two surfaces of aluminum foil, drying the electrode plates, and mixing the electrode plates according to a ratio of 2.45 g/cm ³ Compacting the compacted density, and finally die-cutting the compacted density into a specified size to obtain the positive electrode plate.

Graphite, SP, a binder CMC (carboxymethyl cellulose) and a binder SBR (styrene butadiene rubber emulsion) are mixed according to the mass ratio of 96.0:1.0:1.0:2.0 uniformly dispersing in deionized water, fully stirring under vacuum environment to obtain uniformly mixed anode slurry with solid content of 50%, uniformly coating the anode slurry on copperThe pole pieces were dried on both surfaces of the foil and pressed 1.6 g/cm ³ Compacting the compacted density, and finally die-cutting the compacted density into a specified size to obtain the negative electrode plate.

And finally, combining the positive electrode plate, the negative electrode plate and the polyethylene diaphragm to form a battery, and putting the battery into an aluminum plastic film for drying.

The one-shot method according to the foregoing examples and comparative examples includes injecting an electrolyte into a battery, fluidizing the battery to exhaust gas using a 0.1C current, and then packaging the battery.

The secondary liquid injection method according to the foregoing examples and comparative examples includes injecting a first electrolyte into a battery, pre-forming 40% with a 0.1C current, then exhausting the gas, then injecting a second electrolyte into the battery, and finally packaging the battery after forming 100% as a main.

The batteries of the foregoing examples and comparative examples were subjected to rate charging performance tests, respectively, by constant-current charging to 3.65V at 1C,2C,3C,4C and 5C, to constant-voltage charging to 0.05C, and discharging to 2.5V at 1C, and the constant-current charging ratios at each charging rate were counted, and the test results are shown in table 1, and as can be seen from the data of comparative examples 1 and 1-2, the interface solvation structure can be effectively adjusted by adding the fluorophenylcarboxylate additive, and the desolvation behavior of the negative electrode surface can be facilitated by virtue of the large p-pi conjugated system promoted by the benzene ring structure, so that the negative electrode lithium intercalation kinetics can be greatly improved, and the quick charging performance of the battery can be effectively improved; as can be seen from the data of comparative examples 2-5 and comparative examples 3-5, the addition of the fluorocarbonate additive and the phosphite additive to the first electrolyte serves to form a stable interfacial film first and protect the interface between the positive electrode and the negative electrode, and the addition of the fluorophenyl carboxylate additive to the second electrolyte can effectively improve the fast charge performance of the battery; the data of comparative examples 2-5 show that the battery fast charge performance is optimal when the amount of the fluorophenylcarboxylate additive added is 2.5%.

The batteries of the previous examples and comparative examples were subjected to 45 ℃ cycle performance test, a 2C/2C charge-discharge cycle system was adopted, the voltage range was 2.5V-3.65V, and the capacity retention rate after 800 cycles of each scheme was counted based on the discharge capacity of the first cycle of complete charge-discharge, and the test results are shown in fig. 1 and table 1, and as can be seen from the data of comparative examples 1 and comparative examples 1-2, the addition of the fluorophenylcarboxylate additive effectively improved the high temperature cycle performance of the battery; as can be seen from the data of comparative examples 2-5 and comparative examples 3-5, the fluorocarbonate additive is consumed as much as possible after the first injection, so that the battery capacity attenuation caused by the decomposition of the fluorocarbonate additive at high temperature is effectively inhibited, the negative electrode interface charge transfer is improved, and the high-temperature cycle performance of the battery can be effectively improved by adding the fluorophenyl carboxylate additive into the second electrolyte; the data of comparative examples 2-5 show that the high temperature cycle performance of the cell is best when the amount of the fluorophenylcarboxylate additive added is 2.5%.

Table 1 comparison of rate charging performance and 45 ℃ cycle performance of the batteries

The batteries of the previous examples and comparative examples were subjected to low temperature charging performance tests, wherein a charge-discharge cycle system of 0.33C/0.33C was adopted at each temperature, constant current charging was performed at 25 ℃ to 3.65V, constant voltage charging was performed to 0.05C, discharging was performed to 2.0V, and then cooling was performed to 0 ℃, -10 ℃, -20 ℃, and-30 ℃, constant current charging was performed to 3.65V, discharging was performed to 2.0V, and the discharge capacity retention rate of each temperature with respect to 25 ℃ was counted based on the discharge capacity at 25 ℃, and the test results are shown in table 2, and as can be seen from the data of comparative examples 1 and comparative examples 1-2, the addition of the fluorophenylcarboxylate additive was effective in improving the low temperature performance of the batteries; as can be seen from the data of comparative examples 2-5 and comparative examples 3-5, the electrolyte still has certain fluidity at low temperature, and the fluoro phenyl carboxylate additive is placed in the second electrolyte, so that the interface solvation structure is regulated and controlled, the desolvation is promoted, and the low-temperature performance of the battery is improved; the data of comparative examples 2-5 show that the low temperature performance of the cell is best when the amount of the fluorophenylcarboxylate additive added is 2.5%.

The batteries of the previous examples and the comparative examples are subjected to a cycle performance test at-10 ℃, a charge-discharge cycle system of 0.2C/0.33C is adopted, the voltage range is 2.0V-3.65V, the capacity retention rate of each scheme when the batteries are cycled to 100 circles is counted based on the discharge capacity of the first circle of complete charge-discharge, the test results are shown in fig. 2 and table 2, and the data of the comparative examples 1 and the comparative examples 1-2 show that the low-temperature cycle performance of the batteries can be effectively improved by adding the fluorinated phenyl carboxylate additive; as can be seen from the data of comparative examples 2-5 and comparative examples 3-5, the addition of the fluorophenylcarboxylate additive to the second electrolyte significantly improved the low temperature cycle performance of the battery; the data of comparative examples 2-5 show that the low temperature cycling performance of the cell is best when the amount of the fluorophenylcarboxylate additive added is 2.5%.

Table 2 comparison of low temperature charging performance and-10 ℃ cycle performance of the batteries

The batteries of the previous examples and comparative examples were subjected to a 60 ℃ storage performance test, after each of the batteries of the schemes was formed, the batteries were charged to 3.65V at constant current, and then charged to 0.05C at constant voltage, and were taken out and stored in a 60 ℃ oven, and the residual capacity and recovery capacity of each of the schemes during two months of storage were counted, and the test results are shown in table 3, and as can be seen from the data of comparative examples 1 and comparative examples 1-2, the addition of the fluorophenylcarboxylate additive was effective in improving the storage performance of the batteries; as can be seen from the data of comparative examples 2-5 and comparative examples 3-5, the in-situ complexing between the fluorocarbonate additive and the phosphite additive effectively decomposes the fluorocarbonate additive into a stable interfacial film after the first injection, reduces the decomposition thereof at high temperature, relieves the deterioration of the high temperature storage performance of the battery, and the addition of the fluorophenyl carboxylate additive in the second electrolyte can significantly improve the storage performance of the battery; the data of comparative examples 2-5 show that the best cell storage performance is obtained when the amount of the fluorophenylcarboxylate additive added is 2.5%.

Table 3 comparison of 60 ℃ storage performance of cells

Those of ordinary skill in the art will appreciate that: the discussion of any of the embodiments above is merely exemplary and is not intended to suggest that the scope of the application (including the claims) is limited to these examples; the technical features of the above embodiments or in the different embodiments may also be combined within the idea of the present application, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

In addition, where details are set forth to describe example embodiments of the present application, it will be apparent to one skilled in the art that embodiments of the present application may be practiced without, or with variation of, these details. Accordingly, the description is to be regarded as illustrative in nature and not as restrictive.

Well-known power/ground connections to other components may or may not be shown in the drawings provided to simplify the illustration and discussion, and so as not to obscure the embodiments of the present application. Furthermore, the devices may be shown in block diagram form in order to avoid obscuring the embodiments of the present application, and this also takes into account the fact that specifics with respect to implementation of such block diagram devices are highly dependent upon the platform on which the embodiments of the present application are to be implemented (i.e., such specifics should be well within purview of one skilled in the art). Where specific details are set forth in order to describe example embodiments of the present application, it should be apparent to one skilled in the art that embodiments of the present application may be practiced without, or with variation of, these specific details. Accordingly, the description is to be regarded as illustrative in nature and not as restrictive.

While the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of those embodiments will be apparent to those skilled in the art in light of the foregoing description. The present embodiments are intended to embrace all such alternatives, modifications and variances which fall within the broad scope of the appended claims. Accordingly, any omissions, modifications, equivalents, improvements and/or the like which are within the spirit and principles of the embodiments are intended to be included within the scope of the present application.

Claims

1. A fast charge electrolyte comprising a lithium salt, a carbonate solvent, a carboxylate solvent, a vinylene carbonate, a fluorocarbonate additive, a phosphite additive, a sulfur-containing additive, and a fluorophenylcarboxylate additive; the quick-charging electrolyte comprises a first electrolyte for first liquid injection of the battery and a second electrolyte for second liquid injection of the battery, wherein the battery after the first liquid injection is subjected to pre-formation, and the battery after the second liquid injection is subjected to main formation;

the first electrolyte comprises 11-15 parts by weight of the lithium salt, 45-60 parts by weight of the carbonate solvent, 25-35 parts by weight of the carboxylate solvent, 1.5-2.5 parts by weight of the vinylene carbonate, 0.2-1.5 parts by weight of the fluorocarbonate additive, and 0.1-1 parts by weight of the phosphite additive;

The second electrolyte comprises 11-15 parts by weight of the lithium salt, 40-50 parts by weight of the carbonate solvent, 20-25 parts by weight of the carboxylate solvent, 3.5-9.5 parts by weight of the vinylene carbonate, 2.5-10 parts by weight of the sulfur-containing additive, and 1-5 parts by weight of the fluorophenylcarboxylate additive;

the chemical formula of the fluorinated phenyl carboxylate additive is as follows:

，

wherein R is a perhalogenated aryl group or a perhalogenated alkyl group having 1 to 6 carbon atoms, at least one of R1, R2, R3, R4 and R5 is fluorine, and the balance is halogen.

2. The quick charge electrolyte of claim 1, wherein the lithium salt is one or more of lithium hexafluorophosphate, lithium bis-fluorosulfonyl imide, or lithium bis-trifluoromethylsulfonyl imide;

the carbonic ester solvent is one or more of ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate or propylene carbonate;

the carboxylic ester solvent is one or more of methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl formate or ethyl formate;

the fluorocarbonate additive is one or more of fluoroethylene carbonate, monofluoromethylethylene carbonate, difluoromethyl ethylene carbonate or trifluoromethyl ethylene carbonate;

The phosphite additive is one or more of tris (trimethylsilane) phosphite, triphenyl phosphite, trimethyl phosphite or tris (2, 2-trifluoroethyl) phosphite;

the sulfur-containing additive is one or more of vinyl sulfate, methylene methane disulfonate, 1, 3-propane sultone or propenyl-1, 3-sultone;

the fluoro phenyl carboxylate additive is pentafluorophenyl trifluoroacetate or 2,3,4,5, 6-pentafluoro-2, 3,4,5, 6-pentafluorophenyl benzoate.

3. The quick charge electrolyte of claim 1 wherein the second electrolyte comprises 2.5 parts by weight of the fluorophenylcarboxylate additive.

4. The quick charge electrolyte of claim 1 wherein the lithium salt is lithium hexafluorophosphate, the carbonate solvent is ethylene carbonate and dimethyl carbonate, the carboxylate solvent is ethyl acetate, the fluorocarbonate additive is fluoroethylene carbonate, the phosphite additive is tris (trimethylsilane) phosphite, the sulfur-containing additive is ethylene sulfate, methylene methane disulfonate and 1, 3-propane sultone, and the fluorophenylcarboxylate additive is pentafluorophenyl trifluoroacetate.

5. The quick charge electrolyte of claim 1, wherein the first electrolyte comprises 70-90% by mass of the quick charge electrolyte.

6. A battery filling method, characterized in that the quick-charge electrolyte according to any one of claims 1 to 5 is used, the battery filling method comprising:

performing first liquid injection on the battery by using the first electrolyte;

pre-forming the battery after the first liquid injection;

performing secondary injection on the battery by using the second electrolyte;

and carrying out primary formation on the battery after the secondary liquid injection.

7. A battery comprising a positive electrode, a negative electrode, a separator, and the fast-charging electrolyte of any one of claims 1-4.